Medical swabs in general are known in the art for use in collecting biological specimens from a patient. Such medical swabs commonly comprise an enlarged swab tip of absorbent material on one end of an elongated swab shaft used to direct the swab into contact with a chosen sampling site to collect a specimen on the swab tip. Typically, suspensions of the collected specimen are then prepared for subsequent analysis by immersing the specimen-coated swab tip directly into an appropriate liquid e.g. buffer or saline solution optionally containing an extraction agent such as detergent, nitrous acid, enzyme or the like, using a swirling action to release and disperse the specimen into the liquid.
When a small volume of suspension, such as a volume measurable in microlitres (.mu.l) is prepared by swab immersion, it becomes critically important to express liquid efficiently from the absorbent swab tip before disposing of the swab, so that an adequate volume of the prepared suspension can be recovered for subsequent analysis.
Expression of liquid from the swab tip is routinely attempted by rolling and pressing the swab tip against an internal wall of the container in which the suspension has been prepared. However, the inefficiency with which liquid is expressed using this technique has prompted the use of mechanical aids that enhance expression of swab-absorbed liquid. One such mechanical aid is available as a component of a kit for diagnosing Strep throat infection sold under the name TestPack.TM. by Abbott Laboratories. The mechanical aid is a conical tube of deformable plastic adapted to accommodate a swab tip and to contain liquid expressed therefrom. In use, the specimen-coated swab tip is placed into the tube with an extraction solution, the swab is twirled to release specimen and then the swab is withdrawn. As the swab is withdrawn, the tube is deformed by squeezing to engage the tip while the swab is rotated, in an effort to express liquid thoroughly from the swab into the tube. The efficiency with which liquid is removed from the swab when the tube is used is thus entirely dependent on the user's ability properly to coordinate the actions of squeezing and twirling. Further, the actions required to manipulate the swab and tube can be tiresome for clinicians or analysts who may perform dozens or even hundreds of such tests in a single day.
An object of the present invention is to provide a device which facilitates the expression of absorbed liquid from a swab tip in an efficient manner.